 I'm listening to streams because their sound can tell us a lot about how stream ecosystems function. And this is important because streams provide a lot of ecosystem services to us humans. And many of these services are limited by how fast gases can exchange between air and water. For example, oxygen needs to end the streams in order to improve water quality, or greenhouse gases can evade and that would affect climate warming. Now the magnitude and controls of air with the gas exchange, they are poorly quantified, mainly because our methods we use today require a lot of labor and time. Now we developed a new method that is based on the sound of flowing water. So we record the sound of streams above and below the water surface. And this is based on the idea that the processes that drive air-water gas exchange, including turbulence and bubbles, are also the processes that characterize the specific sound of streams. With lab and field experiments in northern Sweden we were able to find a good relationship between air-water gas exchange velocities and characteristic sound signatures. And we were even able to start disentangling the different processes that drive air-water gas exchange. With this new method we will be able to collect a lot more data than previously and this will improve our understanding of stream ecosystem functioning.